Conventionally, there have been proposed various types of seatbelt retractors which prevent a webbing from being drawn out in case of an emergency.
For instance, in a conventional seatbelt retractor, a U-shaped frame 2 has right and left side walls 2a and 2b with through holes 2d and 2e provided therein, respectively. The right and left side walls 2a and 2b have V-shaped teeth 2f and 2g formed on entire inner peripheries thereof, respectively. Between the right and left side walls 2a and 2b, a reel shaft 4 is arranged for taking up a webbing 3.
The reel shaft 4 has a webbing take-up portion 4a. The webbing take-up portion 4a has circular guide flange portions 4b and 4c formed at both the right and left ends thereof. On outer peripheral portions of the guide flange portions 4b and 4c, arc-like slip-off prevention flanges 4m and 4r are formed. The maximum diameter of outer peripheries formed by the guide flange portions 4b and 4c and the slip-off prevention flanges 4m and 4r is set slightly smaller than the inner peripheral diameter defined by the tips of teeth 2f and 2g, so that the guide flange portions 4b and 4c including the slip-off prevention flanges 4m and 4r is passable through the through holes 2d and 2e, respectively.
The guide flange portions 4b and 4c rotatably support a main pawl 17 and a back-up pawl 20, respectively, on the side opposite to the slip-off prevention flanges 4m and 4r, with regard to the center thereof. The main pawl 17 and the back-up pawl 20 are configured to respectively engage with the teeth 2f and 2g if needed, to prevent rotation of the reel shaft 4 in a webbing pull-out direction. Web-like large misalignment preventing flanges 17g and 20g are formed between the teeth 17d of the main pawl 17 and between the teeth 20d of the back-up pawl 20, on the reel shaft 4 side. The teeth 17d and the teeth 20d are configured to engage with the teeth 2f and 2g, respectively.
The slip-off prevention flanges 4m and 4r face the teeth 2f and 2g, respectively, under a state where the center of each of the through holes 2d and 2e is in line with the center axis of the reel shaft 4 after passing the reel shaft 4 through the through holes 2d and 2e. The large misalignment preventing flanges 17g and 20g are configured to make contact with the insides of the teeth 2f and 2g when the teeth 17d of the main pawl 17 and the teeth 20d of the back-up pawl 20 engage with the teeth 2f and 2g, respectively (See, for instance, Japanese Laid-open Patent Application Publication No. 7-144605).